Interfacial engineering through lead binding using crown ethers in perovskite solar cells

In the domain of perovskite solar cells(PSCs),the imperative to reconcile impressive photovoltaic performance with lead-related issue and environmental stability has driven innovative solutions.This study pioneers an approach that not only rectifies lead leakage but also places paramount importance on the attainment of rigorous interfacial passivation.Crown ethers,notably benzo-18-crown-6-ether(B18C6),were strategically integrated at the perovskite-hole transport material interface.Crown ethers exhibit a dual role:efficiently sequestering and immobilizing Pb^(2+)ions through host-guest complexation and simultaneously establishing a robust interfacial passivation layer.Selected crown ether candidates,guided by density functional theory(DFT)calculations,demonstrated proficiency in binding Pb2+ions and optimizing interfacial energetics.Photovoltaic devices incorporating these materials achieved exceptional power conversion efficiency(PCE),notably 21.7%for B18C6,underscoring their efficacy in lead binding and interfacial passivation.Analytical techniques,including time-of-flight secondary ion mass spectrometry(ToF-SIMS),ultraviolet photoelectron spectroscopy(UPS),time-resolved photoluminescence(TRPL),and transient absorption spectroscopy(TAS),unequivocally affirmed Pb^(2+)ion capture and suppression of non-radiative recombination.Notably,these PSCs maintained efficiency even after enduring 300 h of exposure to 85%relative humidity.This research underscores the transformative potential of crown ethers,simultaneously addressing lead binding and stringent interfacial passivation for sustainable PSCs poised to commercialize and advance renewable energy applications.

Improving the operational stability of perovskite solar cells with cesium-doped graphene oxide interlayer

Perovskite solar cells(PSCs)have made great advances in terms of power conversion efficiency(PCE),yet their subpar stability continues to hinder their commercialization.The interface between the perovskite layer and the charge-carrier transporting layers plays a crucial role in undermining the stability of PSCs.In this work,we propose a strategy to stabilize high-performance PSCs with PCE over 23%by introducing a cesium-doped graphene oxide(GO-Cs)as an interlayer between the perovskite and hole-transporting material.The GO-Cs treated PSCs exhibit excellent operational stability with a projected T80(the time where the device PCE reduces to 80%of its initial value)of 2143 h of operation at the maximum powering point under one sun illumination.

High-Performance Perovskite Solar Cells with Zwitterion-Capped-ZnO Quantum Dots as Electron Transport Layer and NH_(4)X(X=F,Cl,Br)Assisted Interfacial Engineering

The systematic advances in the power conversion efficiency(PCE)and stability of perovskite solar cells(PSCs)have been driven by the developments of perovskite materials,electron transport layer(ETL)materials,and interfacial passivation between the relevant layers.While zinc oxide(ZnO)is a promising ETL in thin film photovoltaics,it is still highly desirable to develop novel synthetic methods that allow both fine-tuning the versatility of ZnO nanomaterials and improving the ZnO/perovskite interface.Among various inorganic and organic additives,zwitterions have been effectively utilized to passivate the perovskite films.In this vein,we develop novel,well-characterized betaine-coated ZnO QDs and use them as an ETL in the planar n-i-p PSC architecture,combining the ZnO QDs-based ETL with the ZnO/perovskite interface passivation by a series of ammonium halides(NH_(4)X,where X=F,Cl,Br).The champion device with the NH4F passivation achieves one of the highest performances reported for ZnO-based PSCs,exhibiting a maximum PCE of~22%with a high fill factor of 80.3%and competitive stability,retaining~78%of its initial PCE under 1 Sun illumination with maximum power tracking for 250 h.

Development of an Integrated CMUTs-Based Resonant Biosensor for Label-Free Detection of DNA with Improved Selectivity by Ethylene-Glycol Alkanethiols

Gravimetric resonant-inspired biosensors have attracted increasing attention in industrial and point-ofcare applications,enabling label-free detection of biomarkers such as DNA and antibodies.Capacitive micromachined ultrasonic transducers(CMUTs)are promising tools for developing miniaturized highperformance biosensing complementary metal–oxide–silicon(CMOS)platforms.However,their operability is limited by inefficient functionalization,aggregation,crosstalk in the buffer,and the requirement for an external high-voltage(HV)power supply.In this study,we aimed to propose a CMUTs-based resonant biosensor integrated with a CMOS front–end interface coupled with ethylene–glycol alkanethiols to detect single-stranded DNA oligonucleotides with large specificity.The topography of the functionalized surface was characterized by energy-dispersive X-ray microanalysis.Improved selectivity for onchip hybridization was demonstrated by comparing complementary and non-complementary singlestranded DNA oligonucleotides using fluorescence imaging technology.The sensor array was further characterized using a five-element lumped equivalent model.The 4 mm^(2) application-specific integrated circuit chip was designed and developed through 0.18 lm HV bipolar-CMOS-double diffused metal–oxide–silicon(DMOS)technology(BCD)to generate on-chip 20 V HV boosting and to track feedback frequency under a standard 1.8 V supply,with a total power consumption of 3.8 mW in a continuous mode.The measured results indicated a detection sensitivity of 7.943×10^(-3) lmol·L^(-1)·Hz^(-1) over a concentration range of 1 to 100 lmol·L^(-1).In conclusion,the label-free biosensing of DNA under dry conditions was successfully demonstrated using a microfabricated CMUT array with a 2 MHz frequency on CMOS electronics with an internal HV supplier.Moreover,ethylene–glycol alkanethiols successfully deposited self-assembled monolayers on aluminum electrodes,which has never been attempted thus far on CMUTs,to enhance the selectivity of bio-functionalization.The findings of this study indicate the possibility of full-on-chip DNA biosensing with CMUTs.

Study of borohydride ionic liquids as hydrogen storage materials

Stability of borohydrides is determined by the localization of the negative charge on the boron atom.Ionic liquids(ILs) allow to modify the stability of the borohydrides and promote new dehydrogenation pathways with a lower activation energy. The combination of borohydride and IL is very easy to realize and no expensive rare earth metals are required. The composite of the ILs with complex hydrides decreases the enthalpy and activation energy for the hydrogen desorption. The Coulomb interaction between borohydride and IL leads to a destabilization of the materials with a significantly lower enthalpy for hydrogen desorption. Here, we report a simple ion exchange reaction using various ILs, such as vinylbenzyltrimethylammonium chloride([VBTMA][Cl]), 1-butyl-3-methylimidazolium chloride([bmim][Cl]), and 1-ethyl-1-methylpyrrolidinium bromide([EMPY][Br]) with NaBH4 to decrease the hydrogen desorption temperature. Dehydrogenation of 1-butyl-3-methylimidazolium borohydride([bmim][BH4]) starts below 100℃. The quantity of desorbed hydrogen ranges between 2.4 wt% and 2.9 wt%, which is close to the theoretical content of hydrogen. The improvement in dehydrogenation is due to the strong amine cation that destabilizes borohydride by charge transfer.

A Technical Review of Hydro-Project Development in China

This paper summarizes the development of hydro-projects in China,blended with an international perspective.It expounds major technical progress toward ensuring the safe construction of high dams and river harnessing,and covers the theorization of uneven non-equilibrium sediment transport,inter-basin water diversion,giant hydro-generator units,pumped storage power stations,underground caverns,ecological protection,and so on.

Laboratory study of fracture initiation and propagation in Barre granite under fluid pressure at stress state close to failure

Hydraulic fracturing is frequently used to increase the permeability of rock formations in energy extraction scenarios such as unconventional oil and gas extraction and enhanced geothermal systems(EGSs).The present study addresses uncertainties in the hydraulic fracturing process pertaining to EGSs in crystalline rock such as granite.Specifically,there is debate in the literature on the mechanisms(i.e.tensile and/or shear)by which these fractures initiate,propagate,and coalesce.We present experiments on Barre granite with pre-cut flaws where the material is loaded to high far-field stresses close to shear failure,and then the fluid pressure in the flaws is increased to move the Mohr’s circle to the left and observe the initiation and propagation of fractures using high-speed imaging and acoustic emissions(AEs).We find that the hydraulic fractures initiate as tensile microcracks at the flaw tips,and then propagate as a combination of tensile and shear microcracks.AE focal mechanisms also show elevated levels of tensional microfracturing near the flaw tips during pressurization and final failure.We then consider a numerical model of the experimental setup,where we find that fractures are indeed likely to initiate at flaw tips in tension even at relatively high far-field stresses of 40 MPa where shear failure is generally expected.

Emergence of Friedmann Equation of Cosmology of a Flat Universe from the Time-Energy Uncertainty Principle

Friedmann equation of cosmology is based on the field equations of general relativity. Its derivation is straight-forward once the Einstein’s field equations are given and the derivation is independent of quantum mechanics. In this paper, it is shown that the Friedmann equation pertinent to a homogeneous, isotropic and flat universe can also be obtained as a consequence of the energy balance in the expanding universe between the positive energy associated with vacuum and matter, and the negative gravitational energy. The results obtained here is a clear consequence of the fact that the surface area of the Hubble sphere is proportional to the total amount of information contained within it.

Battery Charger for Electric Vehicles based on a Wireless Power Transmission

In this paper,the case of a battery charger for electric vehicles based on a wireless power transmission is addressed.The specificity of every stage of the overall system is presented.Based on calculated and measured results,relevant capacitive compensations of the transformer and models are suggested and discussed in order to best match the operating mode and aiming at simplifying as much as possible the control and the electronics of the charger.

Cryptanalysis of the Double-Moduli Cryptosystem

In this article we present a lattice attack done on a NTRU-like scheme introduced by Verkhovsky in [1]. We show how, based on the relation between the public and private key, we can construct an attack which allows any passive adversary to decrypt the encrypted messages. We explain, step by step, how an attacker can construct an equivalent private key and guess what the original plaintext was. Our attack is efficient and provides good experimental results.

An Analytical Model for the Electrolyser Performance Derived from Materials Parameters

Hydrogen is seen as a key element for the transition from a fossil fuel based economy to a renewable, sustainable economy. Hydrogen can be used either directly as an energy carrier or as a feedstock for the reduction of CO2 to synthetic hydrocarbons. Hydrogen can be produced by electrolysis, decomposing water in oxygen and hydrogen. This paper presents an overview of the three major electrolysis technologies: acidic (PEM), alkaline (AEL) and solid oxide electrolysis (SOEC). An updated list of existing electrolysers and commercial providers is provided. Most interestingly, the specific prices of commercial devices are also given when available. Despite tremendous development of the PEM technology in the past decades, the largest and most efficient electrolysers are still alkaline. Thus, this technology is expected to play a key role in the transition to the hydrogen society. A detailed description of the components in an alkaline electrolyser and an analytical model of the process are provided. The analytical model allows investigating the influence of the different operating parameters on the efficiency. Specifically, the effect of temperature on the electrolyte conductivity—and thus on the efficiency—is analyzed. It is found that in the typical range of operating temperatures for alkaline electrolysers of 65°C - 220°C, the efficiency varies by up to 3.5 percentage points, increasing from 80% to 83.5% at 65°C and 220°C, respectively.

Geomechanical analysis of the influence of CO2 injection location on fault stability

Large amounts of carbon dioxide(CO2) should be injected in deep saline formations to mitigate climate change,implying geomechanical challenges that require further understanding.Pressure build-up induced by CO2injection will decrease the effective stresses and may affect fault stability.Geomechanical effects of overpressure induced by CO2injection either in the hanging wall or in the foot wall on fault stability are investigated.CO2injection in the presence of a low-permeable fault induces pressurization of the storage formation between the injection well and the fault.The low permeability of the fault hinders fluid flow across it and leads to smaller overpressure on the other side of the fault.This variability in the fluid pressure distribution gives rise to differential total stress changes around the fault that reduce its stability.Despite a significant pressure build-up induced by the fault,caprock stability around the injection well is not compromised and thus,CO2leakage across the caprock is unlikely to happen.The decrease in fault stability is similar regardless of the side of the fault where CO2is injected.Simulation results show that fault core permeability has a significant effect on fault stability,becoming less affected for high-permeable faults.An appropriate pressure management will allow storing large quantities of CO2without inducing fault reactivation.

UDNS or LES, That Is the Question

In the framework of the spectral element method, a comparison is carried out on turbulent first-and second-order statistics generated by large eddy simulation (LES), under-resolved (UDNS) and fully resolved direct numerical simulation (DNS). The LES is based on classical models like the dynamic Smagorinsky approach or the approximate deconvolution method. Two test problems are solved: the lid-driven cubical cavity and the differentially heated cavity. With the DNS data as benchmark solutions, it is shown that the numerical results produced by the UDNS calculation are of the same accuracy, even in some cases of better quality, as the LES computations. The conclusion advocates the use of UDNS and calls for improvement of the available algorithms.

Leader-follower:Human-centered intention-guided controller for novel SuperLimb with application to load-carrying scenarios

Supernumerary robotic arms(SuperLimb)are a new type of wearable robot that works closely with humans as a third hand to augment human operation capability.Accurate conveyance of wearers'intentions,allocation of roles,and humancentered interaction considerations are the key points in the process of human-SuperLimb collaboration.This paper proposes a human-centered intention-guided leader-follower controller that relies on the dynamic modeling of SuperLimb with application to load-carrying scenarios.The proposed leader-follower controller takes the human as the leader and the SuperLimb as the follower,achieving effective information communication,autonomous coordination,and good force compliance between SuperLimb,humans,and the environment under human safety assurance.First,the human-SuperLimb dynamic system is modeled to achieve force interaction with the environment and wearer.Second,to achieve the precise intention extraction of humans,pose data from five visual odometry sensors are fused to capture the human state,the generalized position,the velocity of hands,and the surface electromyography signals from two myoelectric bracelets sensors are processed to recognize the natural hand gestures during load-carrying scenarios by a designed Swin transformer network.Then,based on the real-time distance detection between human and mechanical limbs,the security assurance and force-compliant interaction of the human-SuperLimb system are realized.Finally,the human hand muscle intention recognition,human-robot safety strategy verification,and comparative load-carrying experiments with and without the proposed method are conducted on the SuperLimb prototype.Results showed that the task parameters are well estimated to produce more reasonable planning trajectories,and SuperLimb could well understand the wearer's intentions to switch different SuperLimb actions.The proposed sensor-based human-robot communication framework motivates future studies of other collaboration scenes for SuperLimb applications.

The energy landscape of magnetic materials

Magnetic materials can display many solutions to the electronic-structure problem,corresponding to different local or global minima of the energy functional.In Hartree-Fock or density-functional theory different single-determinant solutions lead to different magnetizations,ionic oxidation states,hybridizations,and inter-site magnetic couplings.The vast majority of these states can be fingerprinted through their projection on the atomic orbitals of the magnetic ions.We have devised an approach that provides an effective control over these occupation matrices,allowing us to systematically explore the landscape of the potential energy surface.We showcase the emergence of a complex zoology of self-consistent states;evenmore so when semi-local density-functional theory is augmented-and typically made more accurate-by Hubbard corrections.Such extensive explorations allow to robustly identify the ground state of magnetic systems,and to assess the accuracy(or not)of current functionals and approximations.

The rule of four:anomalous distributions in the stoichiometries of inorganic compounds

Why are materials with specific characteristics more abundant than others?This is a fundamental question in materials science and one that is traditionally difficult to tackle,given the vastness of compositional and configurational space.We highlight here the anomalous abundance of inorganic compounds whose primitive unit cell contains a number of atoms that is a multiple of four.This occurrence—named here the rule of four—has to our knowledge not previously been reported or studied.Here,we first highlight the rule’s existence,especially notable when restricting oneself to experimentally known compounds,and explore its possible relationship with established descriptors of crystal structures,from symmetries to energies.We then investigate this relative abundance by looking at structural descriptors,both of global(packing configurations)and local(the smooth overlap of atomic positions)nature.Contrary to intuition,the overabundance does not correlate with lowenergy or high-symmetry structures;in fact,structures which obey the rule of four are characterized by low symmetries and loosely packed arrangements maximizing the free volume.We are able to correlate this abundance with local structural symmetries,and visualize the results using a hybrid supervised-unsupervised machine learning method.

Fast prediction of anharmonic vibrational spectra for complex organic molecules

Interpreting Raman and IR vibrational spectra in complex organic molecules lacking symmetries poses a formidable challenge.In this study,we propose an innovative approach for simulating vibrational spectra and attributing observed peaks to molecular motions,even when highly anharmonic,without the need for computationally expensive ab initio calculations.Our approach stems from the time-dependent stochastic self-consistent harmonic approximation to capture quantum nuclear fluctuations in atom dynamics while describing interatomic interaction through state-of-the-art reactive machine-learning force fields.Finally,we employ an isotropic charge model and a bond capacitor model trained on ab initio data to predict the intensity of IR and Raman signals.

Automated all-functionals infrared and Raman spectra

Infrared and Raman spectroscopies are ubiquitous techniques employed in many experimental laboratories,thanks to their fast and non-destructive nature able to capture materials’features as spectroscopic fingerprints.Nevertheless,these measurements frequently need theoretical and computational support in order to unambiguously decipher and assign complex spectra.Linearresponse theory provides an effective way to obtain the higher-order derivatives needed,but its applicability to modern exchange-correlation functionals and pseudopotential formalism remains limited.Here,we devise an automated,open-source,user-friendly approach based on densityfunctional theory and the electric-enthalpy functional to allow seamless calculation fromfirst principles of infrared absorption and reflectivity,together with zone-center phonons,static dielectric tensor.

Predicting electronic screening for fast Koopmans spectral functional calculations

Koopmans spectral functionals are a powerful extension of Kohn-Sham density-functional theory(DFT)that enables the prediction of spectral properties with state-of-the-art accuracy.The success of these functionals relies on capturing the effects of electronic screening through scalar,orbitaldependent parameters.These parameters have to be computed for every calculation,making Koopmans spectral functionalsmore expensive than their DFT counterparts.In this work,we present a machine-learning model that—with minimal training—can predict these screening parameters directly from orbital densities calculated at the DFT level.Weshow in two prototypical use cases that using the screening parameters predicted by this model,instead of those calculated from linear response,leads to orbital energies that differ by less than 20 meV on average.Since this approach dramatically reduces run times with minimal loss of accuracy,it will enable the application of Koopmans spectral functionals to classes of problems that previously would have been prohibitively expensive,such as the prediction of temperature-dependent spectral properties.More broadly,this work demonstrates that measuring violations of piecewise linearity(i.e.,curvature in total energies with respect to occupancies)can be done efficiently by combining frozen-orbital approximations and machine learning.

Compact and effective photon-resolved image scanning microscope

Fluorescence confocal laser-scanning microscopy(LSM)is one of the most popular tools for life science research.This popularity is expected to grow thanks to single-photon array detectors tailored for LSM.These detectors offer unique single-photon spatiotemporal information,opening new perspectives for gentle and quantitative superresolution imaging.However,a flawless recording of this information poses significant challenges for the microscope data acquisition(DAQ)system.We present a DAQ module based on the digital frequency domain principle,able to record essential spatial and temporal features of photons.We use this module to extend the capabilities of established imaging techniques based on single-photon avalanche diode(SPAD)array detectors,such as fluorescence lifetime image scanning microscopy.Furthermore,we use the module to introduce a robust multispecies approach encoding the fluorophore excitation spectra in the time domain.Finally,we combine time-resolved stimulated emission depletion microscopy with image scanning microscopy,boosting spatial resolution.Our results demonstrate how a conventional fluorescence laser scanning microscope can transform into a simple,information-rich,superresolved imaging system with the simple addition of a SPAD array detector with a tailored data acquisition system.We expected a blooming of advanced single-photon imaging techniques,which effectively harness all the sample information encoded in each photon.